Table 2.
Unadjusted and Adjusted Odds Ratios and 95% Confidence Intervals of Cognitive Impairment Comparing Reduced Versus Nonreduced Heart Rate Variability (HRV) of Various HRV Indices
| Unadjusted | Adjusted for Age, Education, and Race | Multivariate Adjusted* | ||||
|---|---|---|---|---|---|---|
| HRV Index | Odds Ratio (95% Confidence Interval) P-value | |||||
| Standard deviation of normal RR intervals | 1.82 (0.95–3.49) | .07 | 2.01 (0.96–4.21) | .06 | 1.75 (0.66–4.61) | .26 |
| Standard deviation of the average normal RR intervals over a 5-minute period | 1.59 (0.83–3.03) | .16 | 1.82 (0.87–3.82) | .11 | 1.54 (0.57–4.19) | .40 |
| Square root of the mean squared differences of successive normal RR intervals | 1.73 (0.90–3.33) | .10 | 3.12 (1.45–6.72) | .004 | 3.37 (1.26–9.03) | .02 |
| Number of interval differences of successive normal RR intervals >50 ms | 1.23 (0.62–2.44) | .55 | 2.05 (0.94–4.48) | .07 | 3.29 (1.14–9.49) | .03 |
| Very low frequency | 1.77 (0.92–3.41) | .09 | 2.17 (1.02–4.62) | .04 | 2.17 (0.79–5.92) | .13 |
| Low frequency | 1.98 (1.03–3.79) | .04 | 2.21 (1.05–4.64) | .04 | 2.59 (0.96–6.97) | .06 |
| High frequency | 2.46 (1.29–4.68) | .006 | 5.44 (2.41–12.2) | <.001 | 6.74 (2.27–20.0) | .001 |
Note: Reduced HRV was defined as the first quartile (25th percentile) of each HRV index; non-reduced HRV was defined as the remaining upper three quartiles.
*
The model included age, race, education, smoking, current drinking, exercise, low physical activity, beta-blocker use, body mass index, left ventricular hypertrophy, short Geriatric Depression Scale score>5, heart rate, systolic and diastolic blood pressure, total cholesterol, interleukin-6, and history of cardiovascular disease and pulmonary disease.